for Highway Construction Page 393 of 71 5 SECTION 5 19 – DRILLED -IN CONCRETED PILES
519.01 Description.
Provide and install steel piles into pre- drilled holes filled with concrete.
519.02 Materials.
1.Piles . Steel piles as shown in the bridge plans.
2.Concrete. Class 40A self -consolidating per 502.01.A.
519.03 Construction Requirements.
Provide a work plan at least three weeks before drilling begins. The work plan must include the following as a minimum:
1.A description of planned drilling methods,
2.Materials and methods to maintain a stable drill hole,
3.Methods for bracing the piles to maintain their position within the specified tolerances,
4.Methods to place concrete around pile bases ,
5.Methods to fill and stabilize the annular space around the piles above the concrete backfill. Do not begin drilling operations until the work plan is approved. After drilling, clean the sidewall in bedrock and bottom of the drilled holes to the Engineer’s satisfaction before installing piles . No more than 1” of loose material is allowed in the drilled hole bottom bef ore placing concrete . This may require the placement of temporary casings, or additional cleaning with compressed air or other cleaning tools and/or methods before installing piles and concrete . Install piles at the drilled hole centers within 0.25” per foot of pile length from the vertical, or batter shown. Ensure the pile position at cutoff is within 2” of the plan location. Ensure the pile orientation is within 15 degrees of that shown. Use braces to keep the piles in the required position before and after placing concrete . Place concrete no later than 72 hours after pile installation. Place concrete from the bottom of the rock socket with a tremie pipe or a concrete pump. Make sure the concrete filling the rock socket excavation flows around the piles and completely fills the rock socket excavation. Maintain piles in the required position as specified above and braced until the concrete has set. Design and construct corrective measures if the pile location or alignment specified above is not met, and if the Engineer determines that corrective measures are necessary. The Department will not pay for the expense, including schedule delays, associated with the corrective measures. Fill the soil portions of the drilled hole with coarse aggregate for concrete to the top of the drilled holes, as specified in Section 520. Remove casing from the hole as the concrete and aggregate is placed, maintaining the concrete and aggregate top above the casing bottom. for Highway Construction Page 394 of 71 5 519.04 Method of Measurement. The Engineer will measure acceptably completed work by the foot from the pile cutoff elevation to the pile tip elevation.
519.05 Basis of Payment .
The Department will pay for acceptable quantities at the contract unit price as follows: Pay Item Pay Unit Concreted Piles ..................................................................................... FT Hole drilling, coarse aggregate for concrete, and casing if used, will be paid for under Section 520, as applicable. Concrete is incidental . for Highway Construction Page 395 of 71 5 SECTION 520 – PREDRILLING FOR PILING
520.01 Description.
Drill and backfill holes in soil and rock to allow piles to be driven to the highest pile tip elev ations and minimum bearing capacities specified or as directed.
520.02 Materials.
Provide temporary steel casings of sufficient strength to resist damage and deformation during installation, extraction, and all soil pressures on the casing. Coarse a ggregate for concrete, size No. 1 ......................................................................... 703.02.C. Pea Gravel ............................................................................................................................... 703.09
520.03 Construction Requirements.
Submit a work plan for predrilling at least 4 weeks before pile driving. The work pl an must include descriptions of the following:
1.Equipment.
2.Materials.
3.Sequence of operations, including:
a.Removal or replacement of piles that do not reach the required penetration.
b.Measures to ensure stability during excavation and backfilling (e.g., prevention of caving and bottom heave).
c.Hole cleanout methods.
d.Coarse aggregate placement .
e.Pulling temporary casing. Do not perform this work without approval of the wor k plan. Drill holes into soil or rock to the highest pile tip elevation(s) specified and with a minimum diameter that is at least 4 inches greater than the H -pile diagonal dimension and 6 inches greater than the pipe pile outside dimension. After drilling, fill the hole to the top with coarse aggregate to make it ready for pile driving. Remove the temporary casing in accordance with the approved work plan during coarse aggregate placement , maintaining the coarse aggregate top above the casing bottom. Fill any remaining voids with coarse aggregate after completing pile driving.
520.04 Method of Measurement.
The Engineer will measure acceptably completed work by the foot.
520.05 Basis of Payment .
The Department will pay for accepted work as follows:
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 429–430 of 768.